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We are currently using a md3000i DELL SAN server with a RAID1.

I would like to access the information on one disk from a workstation.

The hard disk contains 2 LUN but I can only access the first one.

Any ideas how to access the other LUN ?

It is quite important for us because the RAID configuration on the SAN server disappeard and the disk is displayed as empty, but I do know it still contains the data. I am trying to retrieve the data.

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5  
"RAID0" + "I am trying to retreive the data." Fair amount of cognitive dissonance there. –  EEAA May 20 '11 at 15:41
2  
It is quite unclear what you're trying to do - did you have a RAID0 set up as the backing store for your exported iSCSI LUNs? Or did you use the exported iSCSI LUNs in a software-RAID0 (like mdraid)? Do you have just a single disk there? Did you pull it out of the array and connect it to the workstation? Many questions here, maybe you could be just a bit more verbose. –  the-wabbit May 20 '11 at 15:53
    
Hi Syneticon-dj, thanks for your quick reply. I just realized that I wrote RAID0 instead of RAID1, sorry! We have removed one of the 2 disks out of the array and I am trying to read that disk directly on a workstation. The disk has 2 LUN, I can access the first one easily but cannot access the second LUN. –  Dragouf May 20 '11 at 16:13
    
in that case, please edit your question with the correct information. –  EEAA May 20 '11 at 16:13

1 Answer 1

The disk just contains raw data - it has no concept of LUNs. How the data has been arranged on your disk, is entirely up to the implementation on the MD3000i appliance, which is a black box in this respect.

The MD3000i appliance probably has written the metadata about the structure and the configuration of the array to the end of the disk, that's why you seem to be able to access what you've exported as "the first lun". There is probably no safe way to tell where the "second lun" assignment starts, if it is contiguous and if it is safe to just assume that you can read the data in blocks without problems or if more metadata has been embedded in there, breaking your filesystem structures.

If you are avid for trying some data recovery on your own, you might just check out where the last partition of your "first lun" ends, use a disk editor to verify that the data area following your last partition on "first lun" contains a new partition table and copy the data off there to another disk using dd. You also might want to take a look at TestDisk - it would help you with some of the recovery tasks.

Whatever you do to the disk - at least take a full copy using "dd" or some other imaging software first. Better yet, only operate on the copy instead of the original disk. This way you would have a backup that you still could send to some data recovery service if something goes wrong with your own attempts.

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I am trying to find partition from the second lun with testdisk but for the moment I can't find anything. If someone know which testdisk value I have to use to retrieved partitions of the second LUN I'm interested –  Dragouf May 23 '11 at 8:04
    
Have you done a partition search using testdisk? It should have found "second lun" stuff as well, at least when using "deeper search" mode. You would not be able to boot off the "second lun", but at least you could quickly salvage the data from the partitions this way, transfer it to another disk and fix the boot manager afterwards. –  the-wabbit May 24 '11 at 21:46

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